The present invention relates to an oil-cooled type compressor having a mechanism for detecting the percentage content of oil in discharge gases after separation of oil.
As equipment for compressing gas to blow it, the oil-cooled type compressors have been widely known. In the oil-cooled type compressor, since the compressed gas is discharged with oil accompanied, it is necessary to deliver the compressed gas in a clean state with oil removed to the supply destination for compressed gas, and an oil separation recovering portion is provided in the discharge flow passage. In the oil separation recovering portion, first, relatively large-diameter oil particles flown in together with the compressed gas are separated and recovered making use of the collision action and the gravity sinking action in the course that they are collided and reflected on the internal wall surfaces or the like to reduce the percentage content of oil in the compressed gas to 1000 ppm (wt). Further, internally of the oil separation recovering portion is provided an oil separating element using non-woven fabric, for example, such as cellulose fibers, and the compressed gas is delivered passing through the oil separating element. The fine oil particles are captured in the course that the compressed gas passes through the oil separating element, and are separated from the compressed gas. Normally, the percentage content of oil is lowered to 0.5 ppm (wt), and the compressed gas is delivered from the oil separation recovering portion.
The upper limit of the percentage content of oil after separation of oil is decided by the supply destination of the compressed gas, for example, apparatus such as a gas turbine using the compressed gas. In case of the gas turbine, when the percentage content of oil increases, carbide of oil is adhered to a fuel burner nozzle, resulting in poor combustion. To prevent this, it is necessary to always monitor the percentage content of oil. So, in the current circumstances, part of the compressed gas is taken out, which is caused to pass through filter paper only for a fixed time to thereby monitor the percentage content of oil. Further, more specifically, the filter paper through which the compressed gas passed for a fixed time is cleaned by a solvent, oil is dissolved into the solvent after which the solvent is vaporized, and the weight of the residual oil quantity is measured by a chemical balance to calculate the percentage content of oil.
In case of the above-described liquid-quantity measuring method, for obtaining the percentage content of liquid (in the above-described example, the percentage content of oil), a sheet of filter paper is used to measure the residual oil quantity one by one time. In this case, it is necessary to replace filter paper with new one every measurement, which operation need be repeated, thus taking time and failing to continuously carry out the monitoring.
The present invention has been accomplished in order to overcome such a problem as noted above with respect to prior art. There is provided an oil-cooled type compressor having a mechanism capable of always monitoring the percentage content of oil of gases.
For solving the above-described problem, according to the present invention, there is provided an oil-cooled compressor, comprising: a compressor body; a discharge flow passage for leading a compressed gas compressed by said compressor body to outside of said oil-cooled type compressor; a first oil separation means for separating oil discharged accompanied by said compressed gas from said compressed gas; an oil separation recovering portion housing said first oil separation means to recover the separated oil; an oil flow passage for leading the oil recovered by said oil separation recovering portion to an oiling portion within said compressor body through an oil cooler; an inspecting flow passage branched from said discharge flow passage on the downstream side of said oil separation recovering portion and in communication with a portion lower in pressure than said branched point; a second oil separation means capable of separating oil particles from the compressed gas flowing through said inspecting flow passage; and an oil separation detector for detecting that oil separated by said second oil separation means drops from said second oil separation means, said oil separation detector comprising an oil detection means for electrically detecting a state change caused by contact with the oil dropped from said second oil separation means, and a calculating portion for receiving an electric signal from said oil detection means to calculate the percentage content of oil of said compressed gas from said electric signal.
By the constitution as described above, in the oil-cooled type compressor, the percentage content of oil in the compressed gas can be monitored easily and constantly.
In the above-described oil-cooled type compressor, there can be constituted so that said inspecting flow passage is in communication with a suction flow passage which is a flow passage of gas flowing into said compressor body. Or, there can be constituted so that said inspecting flow passage is joined with a discharge flow passage on the downstream side away from said branched point, and a throttle means is interposed between said branched point and said joined point.
In the above-described oil-cooled type compressor, preferably, there is constituted so that said second oil separation means is able to capture fine oil particles than said first oil separation means.
In the above-described oil-cooled type compressor, preferably, said second oil separation means has the shape of a lower part thereof constituted so that the separated oil drops on a fixed position.
In the above-described oil-cooled type compressor, preferably, said second oil separation means has the shape of a lower end thereof constituted to be spherical. Further preferably, there is constituted so that said spherical portion has a slit. By the constitution as described, one droplet of oil quantity is stabilized, and the percentage content of oil can be calculated more accurately.
In the above-described oil-cooled type compressor, said second oil separation means may be constituted so that oil drops on a plurality of positions. By the constitution as described, the interval of dropping of oil droplets is prolonged, and dropping of oil droplets can be detected easily.
In the above-described oil-cooled type compressor, said oil detection means can be constituted by comprising a heat conductor, said heat conductor being installed at a position where the oil separated by said second oil separation means drops, a temperature detector for detecting a temperature of said heat conductor, and a heater for heating said heat conductor, said heater being controlled so that in the state that the oil separated by said second separation means is not dropped, the temperature of said heat conductor is maintained approximately constant. Preferably, there is constituted so that the heat conductor has its lower part to have an elongated shape so as to lead oil downward from the heater or the portion connected with the temperature detector.
By the constitution as described, the oil detection means can be realized by a simple constitution, and is inexpensive and maintenance thereof is facilitated.
Preferably, an oil-proof agent is coated on the heat conductor. With this, liquid is not adhered to the heat transfer plate, and the temperature is recovered quickly. Accordingly, even where the interval of dropping of oil droplets is short, it is possible to detect the dropping of oil droplets.
Further, in the oil-cooled type compressor, there can be constituted so that said oil detection means comprises a load cell, said load cell detecting the shock force when the oil dropped from said second oil separation means impinges upon said oil detection means.
Further, in the oil-cooled type compressor, there can be constituted so that said oil detection means comprises a thin plate supported in a cantilever fashion, said thin plate being installed so that oil separated by said second oil separation means drops on the free end thereof, and a strain gage, said strain gage detecting vibrations of said thin plate.
In the oil-cooled type compressor, there can be constituted so that said calculating portion obtains the oil content from the interval in which the electric signal changes.
Further, in the oil-cooled type compressor having oil detection means comprising a heater and a heat conductor, there can be also constituted so that said calculating portion obtains the oil content from the temperature dropping amount per unit time. By the constitution as described, even where the interval of dropping of oil droplets is so short that the temperature cannot be recovered, the dropping of oil droplets can be detected easily.
In the oil-cooled type compressor, there can be constituted to have a siphon, said siphon storing oil dropped from said second oil separation means and flowing out the stored oil so as to come in contact with said oil detection means. Thereby, even where the quantity of oil separated from the second oil separation means is large, the percentage content of oil can be obtained accurately.
Further, in the oil-cooled type compressor, there can be constituted so as to comprise an oil absorbing member, said oil absorbing member being provided downward of said second oil separation means to absorb oil separated by said second oil separation means, and an electric resistance detection means for detecting the electric resistance of said oil absorbing member. With this, even where the quantity of oil separated by the second oil separation means is small, the percentage content of oil can be obtained accurately.
Further, in the oil-cooled type compressor, there can be constituted so as to comprise a flow rate detection means provided on said inspecting flow passage, said flow rate detection means detecting the flow rate of said compressed gas flowing through said inspecting flow passage. The calculating portion calculates the percentage content of oil of said compressed gas using the flow rate detected by said flow rate detection means. Further, there can be constituted so as to comprise a flow rate control means provided on said inspecting flow passage. Said flow rate control means controls the flow rate of the compressed gas flowing through said inspecting flow passage in response to an electric signal from said oil detection means. By the constitution as described, it is possible, while controlling such that for example, where the interval of dropping is long, the flow rate of gas flowing through the inspecting flow passage is increased, and where the interval of dropping is short, the flow rate of gas flowing through the inspecting flow passage is decreased, to measure the flow rate thereof to obtain the percentage content of oil. Thereby, the interval for computing the percentage content of oil is approximately constant, and where the obtained percentage content of oil is used for controlling the compressor or the like, the stabilized control becomes enabled.